The present invention relates to an ion exchanger vessel, particularly for use in a motor vehicle, having a housing for receiving an ion exchange material and an inlet line and discharge line in the housing for introducing and discharging a liquid to be passed through the ion exchange material.
Ion exchanger vessels of this type are used, for instance, in the exhaust tract of motor vehicles having an internal combustion engine to remove calcium ions from the water content in an aqueous urea solution. This prevents calcium deposits in injection nozzles used to inject the aqueous urea solution into the exhaust stream for oxygen reduction of nitrogen oxides. The ion exchanger decalcifies the water content in the urea solution to increase the life of the components coming into contact with the urea solution.
Because of the relatively high water content in the urea solution (the water content is approximately two-thirds), the problem is encountered that the freezing point of the solution is higher than the temperatures occurring during a hard frost, so that there is a risk that the aqueous solution will freeze.